Are you kidding me!!! Look at the A-pillars, the door bars and all the bracing all around. The doors have cross bars and upper corner bars. The A-pillars are braced to the roll cage. Later on in the post he explains all the seam welding that he did also. That car is VERY rigid!!!
Take a look at
this pic to see what he did to the doors. The one thing that he did WRONG was bracing the front strut towers to the cage. Now that is just a problem waiting to happen. I feel sorry for the passengers feet when they hit something head on!!!